Aerobic exercise and lumbar spine bone mineral density in postmenopausal women: a meta-analysis

Effects of physical exercise on bone mineral density in older postmenopausal women: a systematic review and meta-analysis of randomized controlled trials

Osteoporosis or decreased bone mineral density (BMD) is the most important risk factor for fractures, especially in older postmenopausal women (PMW). However, the interactions between exercise training and bone mineral density are not completely understood. We evaluated the effects of physical exercise on BMD in women aged ≥ 60 years postmenopausal.

PURPOSE

This systematic review and meta-analysis sets out to determine the effects of physical exercise on BMD in older postmenopausal women.

METHODS

A systematic search was conducted in Medline, Science Direct, Cochrane, PubMed, CINAHL, Google Scholar, Scopus, and ProQuest up to December 25, 2021. Fifty-three studies, which assessed a total of 2896 participants (mean age: between 60 and 82 years), were included and analyzed using a random-effects model to estimate weighted mean differences (WMD) with 95% confidence intervals (CI).

RESULTS

The meta-analysis found that exercise training significantly (p < 0.05) increased femoral neck (WMD: 0.01 g/cm²; 95% CI, 0.00 to 0.01], p = 0.0005; I² = 57%; p < 0.0001), lumbar spine (WMD: 0.01 g/cm², 95% CI, 0.01 to 0.02], I² = 81%; p = 0.0001), and trochanter (WMD: 0.01 g/cm², 95% CI 0.00, 0.02]; p = 0.009; I² = 17%; p = 0.23). There were no significant differences between the intervention and control groups for total body and total hip BMD.

CONCLUSION

Our findings suggest that exercise training may improve bone mineral density in older PMW. This improvement is mediated by increases in the femoral neck, lumbar spine, and trochanter BMD. Further long-term studies are required to confirm these findings.

Effect of Tai Chi exercise with the same frequency and different exercise duration on the bone mineral density of older women

BACKGROUND

This study compared the effect of Tai Chi with the same frequency and different session duration on the bone mineral density (BMD) of older women.

METHODS

Healthy older women aged 55-70 years were randomly divided into the short-time group (N.=17), long-time group (N.=18), and control group (N.=17). The BMD of L<inf>2-4</inf> and the proximal femur were measured at baseline and after 48 weeks of intervention.

RESULTS

From 0 to 48 weeks, the respective BMD values of L<inf>2-4</inf> and the femoral neck in the short-time and long-time groups increased by 8.8% and 7.5% (P<0.01) and 8.8% and 12.7% (P<0.01), while the BMD of the greater trochanter in the control group decreased by 3.0% (P<0.05). After 48 weeks, the BMD of L<inf>2-4</inf> and the femoral neck was greater in the short-time and long-time groups than the control group (P<0.001).

CONCLUSIONS

Tai Chi for 30 or 60 minutes five times weekly for 48 weeks improves the BMD of L<inf>2-4</inf> and the femoral neck in older women but does not affect the BMD of the greater trochanter and Ward's triangle. Increasing the exercise duration does not increase the effect of Tai Chi on BMD.

Eating Pattern and Nutritional Risks among People with Multiple Sclerosis Following a Modified Paleolithic Diet

Preliminary studies suggest that a modified Paleolithic diet may benefit symptoms of fatigue in progressive multiple sclerosis (MS). However, this diet restricts the consumption of eggs, dairy, and gluten-containing grains, which may increase the risk of micronutrient deficiencies. Therefore, we evaluated the nutritional safety of this diet among people with progressive MS. Three nonconsecutive 24-h dietary recalls were collected from (n = 19) progressive MS participants in the final months of a diet intervention study and analyzed using Nutrition Data System for Research (NDSR) software. Food group intake was calculated, and intake of micronutrients was evaluated and compared to individual recommendations using Nutrient Adequacy Ratios (NARs). Blood was drawn at baseline and the end of the study to evaluate biomarker changes. Mean intake of fruits and vegetables exceeded nine servings/day and most participants excluded food groups. The intake of all micronutrients from food were above 100% NAR except for vitamin D (29.6 ± 34.6%), choline (73.2 ± 27.2%), and calcium (60.3 ± 22.8%), and one participant (1/19) exceeded the Tolerable Upper Limit (UL) for zinc, one (1/19) for vitamin A, and 37% (7/19) exceeded the chronic disease risk reduction (CDRR) for sodium. When intake from supplements was included in the analysis, several individuals exceeded ULs for magnesium (5/19), zinc (2/19), sodium (7/19), and vitamins A (2/19), D (9/19), C (1/19), B₆ (3/19), and niacin (10/19). Serum values of vitamins D, B₁₂, K₁, K₂, and folate significantly increased compared to respective baseline values, while homocysteine and magnesium values were significantly lower at 12 months. Calcium and vitamin A serum levels did not change. This modified Paleolithic diet is associated with minimal nutritional risks. However, excessive intake from supplements may be of concern.

Exercise Training as Part of Musculoskeletal Management for Congenital Myopathy: Where Are We Now?

Congenital myopathy is a heterogeneous group of muscle disorders characterized by muscle weakness and hypotonia. This condition is associated with a range of skeletal, respiratory, and ophthalmologic complications and requires a multidisciplinary therapeutic approach aimed at maximizing the function and independence of patients. One promising direction for therapeutic intervention is physical exercise rehabilitation, given its demonstrated ability to promote muscle and bone health of patients with a variety of neuromuscular conditions. However, there are few data to assist health care professionals identify the optimal physical activity levels and exercise type, including the intensity, frequency, and duration. This lack of empirical evidence is particularly problematic given the fact that inappropriate exercise modes can potentially cause muscle damage in patients with congenital myopathy. In this article, we discuss the rationale behind the incorporation of two types of physical exercises, strength and aerobic training, into the clinical care of patients with congenital myopathy. Given the paucity of literature on the management of congenital myopathy, we review the results of published research on the treatment of both congenital myopathy and other neuromuscular diseases that could provide helpful insights into the physical rehabilitation of patients with congenital myopathy. We also discuss the potential benefits of vibration therapy, which has been studied in patients with other neuromuscular disorders over the last two decades. We conclude by proposing directions for future research on physical rehabilitation of patients with congenital myopathy.

Impact of calcium, vitamin D, vitamin K, oestrogen, isoflavone and exercise on bone mineral density for osteoporosis prevention in postmenopausal women: a network meta-analysis

The aim of this network meta-analysis is to compare bone mineral density (BMD) changes among different osteoporosis prevention interventions in postmenopausal women. We searched MEDLINE, Embase and Cochrane Library from inception to 24 February 2019. Included studies were randomised controlled trials (RCT) comparing the effects of different treatments on BMD in postmenopausal women. Studies were independently screened by six authors in three pairs. Data were extracted independently by two authors and synthesised using Bayesian random-effects network meta-analysis. The results were summarised as mean difference in BMD and surface under the cumulative ranking (SUCRA) of different interventions. A total of ninety RCT (10 777 participants) were included. Ca, vitamin D, vitamin K, oestrogen, exercise, Ca + vitamin D, vitamin D + vitamin K and vitamin D + oestrogen were associated with significantly beneficial effects relative to no treatment or placebo for lumbar spine (LS). For femoral neck (FN), Ca, exercise and vitamin D + oestrogen were associated with significantly beneficial intervention effects relative to no treatment. Ranking probabilities indicated that oestrogen + vitamin D is the best strategy in LS, with a SUCRA of 97·29 % (mean difference: +0·072 g/cm2 compared with no treatment, 95 % credible interval (CrI) 0·045, 0·100 g/cm2), and Ca + exercise is the best strategy in FN, with a SUCRA of 79·71 % (mean difference: +0·029 g/cm2 compared with placebo, 95 % CrI –0·00093, 0·060 g/cm2). In conclusion, in postmenopausal women, many interventions are valuable for improving BMD in LS and FN. Different intervention combinations can affect BMD at different sites diversely.

Effects of bone-specific physical activity on body composition, bone mineral density, and health-related physical fitness in middle-aged women

PURPOSE

The study aimed to determine the effects of bone-specific physical activity on body composition, bone mineral density (BMD), and health-related physical fitness in middle-aged women.

METHODS

One hundred eighty-six middle-aged women aged 31-49 years participated in this study. The subjects were divided into tertile groups according to the level of physical activity (low-score group, n=62; middle-score group, n=62; high-score group, n=62). Bone-specific physical activity participation was assessed using the bone-specific physical activity questionnaire. Body composition and BMD were measured using dual-energy X-ray absorptiometry. Health-related physical fitness test included isometric muscle strength (grip strength), muscular endurance (sit-ups), flexibility (sit and reach), and cardiorespiratory fitness (maximal oxygen uptake [VO2max]).

RESULTS

The high-score group had a significantly higher fat-free mass (p=.045, partial eta-squared value [ηp2]=.033) than the middle- and low-score groups, whereas the high-score group had significantly lower percent body fat (p=.005, ηp2=.056) than the other two groups. Whole-body BMD (p=.034, ηp2=.036) and lumbar BMD (p=.003, ηp2=.060) were significantly higher in the high-score group than in the low-score group. The high-score group performed significantly better for grip strength (p=.0001, ηp2=.101), sit-ups (p=.0001, ηp2=.108), and VO2max (p=.0001, ηp2=.092) than the other two groups.

CONCLUSION

The present study suggests that bone-specific physical activity could be useful in improving body composition, BMD, and health-related physical fitness in middle-aged women, significantly enhancing their BMD and health conditions.

The Effectiveness of Combined Exercise Interventions for Preventing Postmenopausal Bone Loss: A Systematic Review and Meta-analysis

Study Design Systematic review and meta-analysis. Background It remains unclear whether exercise combining different types of physical activities (combined exercise interventions) would effectively preserve postmenopausal women's bone mineral density (BMD) at different sites. Objective To examine the impact of combined exercise interventions on lumbar spine, femoral neck, total hip, and total body BMD in postmenopausal women. Methods An electronic database search was conducted in PubMed, EMBASE, SPORTDiscus, and Web of Science up to January 1, 2016. Randomized controlled trials that conducted combined exercise interventions and reported BMD values in postmenopausal women were included. Two authors independently extracted the data from individual studies. The primary end point was the change in BMD values from baseline to follow-up. The effect sizes were estimated by the standardized mean difference (SMD) methods using fixed-effects models. Results Eleven randomized controlled trials including 1061 postmenopausal women met the inclusion criteria. The levels of between-study heterogeneity were relatively low (I²<50%). Exercise integrating different physical activities significantly increased lumbar spine (SMD, 0.170; 95% confidence interval [CI]: 0.027, 0.313; P = .019), femoral neck (SMD, 0.177; 95% CI: 0.030, 0.324; P = .018), total hip (SMD, 0.198; 95% CI: 0.037, 0.359; P = .016), and total body (SMD, 0.257; 95% CI: 0.053, 0.461; P = .014) BMD. Combined exercise interventions generated a beneficial effect on femoral neck BMD (SMD, 0.219; 95% CI: 0.034, 0.404; P = .020) in groups with women aged younger than 60 years, and significantly improved lumbar spine BMD (SMD, 0.349; 95% CI: 0.064, 0.634; P = .016) in groups with women aged 60 years or older. Conclusion Our findings suggest that combined exercise interventions appear to be effective in preserving postmenopausal women's BMD at the lumbar spine, femoral neck, total hip, and total body. Level of Evidence Therapy, level 1a. J Orthop Sports Phys Ther 2017;47(4):241-251. Epub 3 Mar 2017. doi:10.2519/jospt.2017.6969.

Effect of swimming exercise on three-dimensional trabecular bone microarchitecture in ovariectomized rats

Swimming is generally considered ineffective for increasing bone mass in humans, at least compared with weight-bearing sports. However, swimming exercise has sometimes been shown to have a strong positive effect on bone mass in small animals. This study investigated the effects of swimming on bone mass, strength, and microarchitecture in ovariectomized (OVX) rats. OVX or sham operations were performed on 18-wk-old female Fisher 344 rats. Rats were randomly divided into four groups: sham sedentary (Sham-CON), sham swimming exercised (Sham-SWI), OVX sedentary (OVX-CON), and OVX swimming exercised (OVX-SWI). Rats in exercise groups performed swimming in a water bath for 60 min/day, 5 days/wk, for 12 wk. Bone mineral density (BMD) in right femurs was analyzed using dual-energy X-ray absorptiometry. Three-dimensional trabecular architecture at the distal femoral metaphysis was analyzed using microcomputed tomography (μCT). Geometrical properties of diaphyseal cortical bone were evaluated in the midfemoral region using μCT. The biomechanical properties of femurs were analyzed using three-point bending. Femoral BMD was significantly decreased following ovariectomy. This change was suppressed by swimming. Trabecular bone thickness, number, and connectivity were decreased by ovariectomy, whereas structure model index (i.e., ratio of rod-like to plate-like trabeculae) increased. These changes were also suppressed by swimming exercise. Femurs displayed greater cortical width and maximum load in SWI groups than in CON groups. Together, these results demonstrate that swimming exercise drastically alleviated both OVX-induced decreases in bone mass and mechanical strength and the deterioration of trabecular microarchitecture in rat models of osteoporosis.

Building healthy bones throughout life: an evidence-informed strategy to prevent osteoporosis in Australia

Osteoporosis imposes a tremendous burden on Australia: 1.2 million Australians have osteoporosis and 6.3 million have osteopenia. In the 2007–08 financial year, 82 000 Australians suffered fragility fractures, of which > 17 000 were hip fractures. In the 2000–01 financial year, direct costs were estimated at $1.9 billion per year and an additional $5.6 billion on indirect costs. Osteoporosis was designated a National Health Priority Area in 2002; however, implementation of national plans has not yet matched the rhetoric in terms of urgency. Building healthy bones throughout life, the Osteoporosis Australia strategy to prevent osteoporosis throughout the life cycle, presents an evidence-informed set of recommendations for consumers, health care professionals and policymakers. The strategy was adopted by consensus at the Osteoporosis Australia Summit in Sydney, 20 October 2011. Primary objectives throughout the life cycle are: to maximise peak bone mass during childhood and adolescence to prevent premature bone loss and improve or maintain muscle mass, strength and functional capacity in healthy adults to prevent and treat osteoporosis in order to minimise the risk of suffering fragility fractures, and reduce falls risk, in older people. The recommendations focus on three affordable and important interventions — to ensure people have adequate calcium intake, vitamin D levels and appropriate physical activity throughout their lives. Recommendations relevant to all stages of life include: daily dietary calcium intakes should be consistent with Australian and New Zealand guidelines serum levels of vitamin D in the general population should be above 50nmol/L in winter or early spring for optimal bone health regular weight-bearing physical activity, muscle strengthening exercises and challenging balance/mobility activities should be conducted in a safe environment.

Bone quality: the determinants of bone strength and fragility

Bone fragility is a major health concern, as the increased risk of bone fractures has devastating outcomes in terms of mortality, decreased autonomy, and healthcare costs. Efforts made to address this problem have considerably increased our knowledge about the mechanisms that regulate bone formation and resorption. In particular, we now have a much better understanding of the cellular events that are triggered when bones are mechanically stimulated and how these events can lead to improvements in bone mass. Despite these findings at the molecular level, most exercise intervention studies reveal either no effects or only minor benefits of exercise programs in improving bone mineral density (BMD) in osteoporotic patients. Nevertheless, and despite that BMD is the gold standard for diagnosing osteoporosis, this measure is only able to provide insights regarding the quantity of bone tissue. In this article, we review the complex structure of bone tissue and highlight the concept that its mechanical strength stems from the interaction of several different features. We revisited the available data showing that bone mineralization degree, hydroxyapatite crystal size and heterogeneity, collagen properties, osteocyte density, trabecular and cortical microarchitecture, as well as whole bone geometry, are determinants of bone strength and that each one of these properties may independently contribute to the increased or decreased risk of fracture, even without meaningful changes in aBMD. Based on these findings, we emphasize that while osteoporosis (almost) always causes bone fragility, bone fragility is not always caused just by osteoporosis, as other important variables also play a major role in this etiology. Furthermore, the results of several studies showing compelling data that physical exercise has the potential to improve bone quality and to decrease fracture risk by influencing each one of these determinants are also reviewed. These findings have meaningful clinical repercussions as they emphasize the fact that, even without leading to improvements in BMD, exercise interventions in patients with osteoporosis may be beneficial by improving other determinants of bone strength.

Influence of weight training on skeletal health of breast cancer survivors with or at risk for breast cancer-related lymphedema

PURPOSE

This study aimed to determine whether the Physical Activity and Lymphedema (PAL) trial weight training program for breast cancer survivors at risk of or with breast cancer-related lymphedema provided skeletal benefits.

METHODS

Of the 295 participants in the randomized controlled PAL trial, 258 (weight training; N = 128; control, N = 130) had complete measures of bone mineral density (BMD (in grams per square centimeter)) of the proximal femur and lumbar spine and were also categorized by T scores. Women in the weight training group performed slowly progressive weight training 2 days/week for 12 months compared to women in the control group who maintained their usual physical activities.

RESULTS

There were no significant differences in the rate of BMD change at any skeletal site between weight training and control groups, regardless of menopausal status. Distribution of bone health categories was not significantly different between groups at baseline, but became different at 12 months (p < 0.03) among postmenopausal women due to an increase in the percentage of controls who became osteopenic (35 to 44%) compared to stable bone health in weight lifters.

CONCLUSIONS

The PAL weight training program that increased muscle strength without exacerbating or causing lymphedema among breast cancer survivors was not as efficacious at improving skeletal health. The skeletal loads produced from the PAL program may be insufficient to notably shift BMD, but may have a subtle osteogenic effect.

IMPLICATIONS FOR CANCER SURVIVORS

The safety and efficacy of rigorous weight training programs for improving skeletal health in women at risk for or with breast cancer-related lymphedema remain to be determined.

A cluster-randomised, controlled trial to assess the impact of a workplace osteoporosis prevention intervention on the dietary and physical activity behaviours of working women: study protocol

Background

Osteoporosis is a debilitating disease and its risk can be reduced through adequate calcium consumption and physical activity. This protocol paper describes a workplace-based intervention targeting behaviour change in premenopausal women working in sedentary occupations.

Method/Design

A cluster-randomised design was used, comparing the efficacy of a tailored intervention to standard care. Workplaces were the clusters and units of randomisation and intervention. Sample size calculations incorporated the cluster design. Final number of clusters was determined to be 16, based on a cluster size of 20 and calcium intake parameters (effect size 250 mg, ICC 0.5 and standard deviation 290 mg) as it required the highest number of clusters.

Sixteen workplaces were recruited from a pool of 97 workplaces and randomly assigned to intervention and control arms (eight in each). Women meeting specified inclusion criteria were then recruited to participate. Workplaces in the intervention arm received three participatory workshops and organisation wide educational activities. Workplaces in the control/standard care arm received print resources. Intervention workshops were guided by self-efficacy theory and included participatory activities such as goal setting, problem solving, local food sampling, exercise trials, group discussion and behaviour feedback.

Outcomes measures were calcium intake (milligrams/day) and physical activity level (duration: minutes/week), measured at baseline, four weeks and six months post intervention.

Discussion

This study addresses the current lack of evidence for behaviour change interventions focussing on osteoporosis prevention. It addresses missed opportunities of using workplaces as a platform to target high-risk individuals with sedentary occupations. The intervention was designed to modify behaviour levels to bring about risk reduction. It is the first to address dietary and physical activity components each with unique intervention strategies in the context of osteoporosis prevention. The intervention used locally relevant behavioural strategies previously shown to support good outcomes in other countries. The combination of these elements have not been incorporated in similar studies in the past, supporting the study hypothesis that the intervention will be more efficacious than standard practice in osteoporosis prevention through improvements in calcium intake and physical activity.

Exercise and bone mineral density in premenopausal women: a meta-analysis of randomized controlled trials

Objective. Examine the effects of exercise on femoral neck (FN) and lumbar spine (LS) bone mineral density (BMD) in premenopausal women. Methods. Meta-analysis of randomized controlled exercise trials ≥24 weeks in premenopausal women. Standardized effect sizes (g) were calculated for each result and pooled using random-effects models, Z score alpha values, 95% confidence intervals (CIs), and number needed to treat (NNT). Heterogeneity was examined using Q and I(2). Moderator and predictor analyses using mixed-effects ANOVA and simple metaregression were conducted. Statistical significance was set at P ≤ 0.05. Results. Statistically significant improvements were found for both FN (7g's, 466 participants, g = 0.342, 95%  CI = 0.132, 0.553, P = 0.001, Q = 10.8, P = 0.22, I(2) = 25.7%, NNT = 5) and LS (6g's, 402 participants, g = 0.201, 95%  CI = 0.009, 0.394, P = 0.04, Q = 3.3, P = 0.65, I(2) = 0%, NNT = 9) BMD. A trend for greater benefits in FN BMD was observed for studies published in countries other than the United States and for those who participated in home versus facility-based exercise. Statistically significant, or a trend for statistically significant, associations were observed for 7 different moderators and predictors, 6 for FN BMD and 1 for LS BMD. Conclusions. Exercise benefits FN and LS BMD in premenopausal women. The observed moderators and predictors deserve further investigation in well-designed randomized controlled trials.

Effects of ground and joint reaction force exercise on lumbar spine and femoral neck bone mineral density in postmenopausal women: a meta-analysis of randomized controlled trials

Background

Low bone mineral density (BMD) and subsequent fractures are a major public health problem in postmenopausal women. The purpose of this study was to use the aggregate data meta-analytic approach to examine the effects of ground (for example, walking) and/or joint reaction (for example, strength training) exercise on femoral neck (FN) and lumbar spine (LS) BMD in postmenopausal women.

Methods

The a priori inclusion criteria were: (1) randomized controlled trials, (2) exercise intervention ≥ 24 weeks, (3) comparative control group, (4) postmenopausal women, (5) participants not regularly active, i.e., less than 150 minutes of moderate intensity (3.0 to 5.9 metabolic equivalents) weight bearing endurance activity per week, less than 75 minutes of vigorous intensity (> 6.0 metabolic equivalents) weight bearing endurance activity per week, resistance training < 2 times per week, (6) published and unpublished studies in any language since January 1, 1989, (7) BMD data available at the FN and/or LS. Studies were located by searching six electronic databases, cross-referencing, hand searching and expert review. Dual selection of studies and data abstraction were performed. Hedge’s standardized effect size (g) was calculated for each FN and LS BMD result and pooled using random-effects models. Z-score alpha values, 95%confidence intervals (CI) and number-needed-to-treat (NNT) were calculated for pooled results. Heterogeneity was examined using Q and I². Mixed-effects ANOVA and simple meta-regression were used to examine changes in FN and LS BMD according to selected categorical and continuous variables. Statistical significance was set at an alpha value ≤0.05 and a trend at >0.05 to ≤ 0.10.

Results

Small, statistically significant exercise minus control group improvements were found for both FN (28 g’s, 1632 participants, g = 0.288, 95% CI = 0.102, 0.474, p = 0.002, Q = 90.5, p < 0.0001, I² = 70.1%, NNT = 6) and LS (28 g’s, 1504 participants, g = 0.179, 95% CI = −0.003, 0.361, p = 0.05, Q = 77.7, p < 0.0001, I² = 65.3%, NNT = 6) BMD. Clinically, it was estimated that the overall changes in FN and LS would reduce the 20-year relative risk of osteoporotic fracture at any site by approximately 11% and 10%, respectively. None of the mixed-effects ANOVA analyses were statistically significant. Statistically significant, or a trend for statistically significant, associations were observed for changes in FN and LS BMD and 20 different predictors.

Conclusions

The overall findings suggest that exercise may result in clinically relevant benefits to FN and LS BMD in postmenopausal women. Several of the observed associations appear worthy of further investigation in well-designed randomized controlled trials.

Effects of training on bone mass in older adults: a systematic review

It is widely recognized that the risk of fractures is closely related to the typical decline in bone mass during the ageing process in both women and men. Exercise has been reported as one of the best non-pharmacological ways to improve bone mass throughout life. However, not all exercise regimens have the same positive effects on bone mass, and the studies that have evaluated the role of exercise programmes on bone-related variables in elderly people have obtained inconclusive results. This systematic review aims to summarize and update present knowledge about the effects of different types of training programmes on bone mass in older adults and elderly people as a starting point for developing future interventions that maintain a healthy bone mass and higher quality of life in people throughout their lifetime. A literature search using MEDLINE and the Cochrane Central Register of Controlled Trials databases was conducted and bibliographies for studies discussing the effect of exercise interventions in older adults published up to August 2011 were examined. Inclusion criteria were met by 59 controlled trials, 7 meta-analyses and 8 reviews. The studies included in this review indicate that bone-related variables can be increased, or at least the common decline in bone mass during ageing attenuated, through following specific training programmes. Walking provides a modest increase in the loads on the skeleton above gravity and, therefore, this type of exercise has proved to be less effective in osteoporosis prevention. Strength exercise seems to be a powerful stimulus to improve and maintain bone mass during the ageing process. Multi-component exercise programmes of strength, aerobic, high impact and/or weight-bearing training, as well as whole-body vibration (WBV) alone or in combination with exercise, may help to increase or at least prevent decline in bone mass with ageing, especially in postmenopausal women. This review provides, therefore, an overview of intervention studies involving training and bone measurements among older adults, especially postmenopausal women. Some novelties are that WBV training is a promising alternative to prevent bone fractures and osteoporosis. Because this type of exercise under prescription is potentially safe, it may be considered as a low impact alternative to current methods combating bone deterioration. In other respects, the ability of peripheral quantitative computed tomography (pQCT) to assess bone strength and geometric properties may prove advantageous in evaluating the effects of training on bone health. As a result of changes in bone mass becoming evident by pQCT even when dual energy X-ray absortiometry (DXA) measurements were unremarkable, pQCT may provide new knowledge about the effects of exercise on bone that could not be elucidated by DXA. Future research is recommended including longest-term exercise training programmes, the addition of pQCT measurements to DXA scanners and more trials among men, including older participants.

Effects of a laughter and exercise program on physiological and psychological health among community-dwelling elderly in Japan: randomized controlled trial

AIM

To examine the effects of a once-weekly laughter and exercise program on physical and psychological health among elderly people living in the community. As a regular exercise program can be difficult to maintain, we provided a more enjoyable program to enhance adherence to exercise.

METHODS

A total of 27 individuals aged 60 years or older, without disabilities, were randomly assigned to either an immediate treatment group (n=14) or a delayed treatment group (n=13). The intervention was a 120-min session consisting of laughter and exercise, carried out once a week for 10 consecutive weeks. Measurements taken at baseline, 3 and 6 months included bodyweight, height, body fat, lean mass, bone mineral density, hemoglobin A1c (HbA(1c)), glucose, high-density lipoprotein and low-density lipoprotein cholesterol, and triglycerides, as well as self-rated health and psychological factors.

RESULTS

All participants completed the 3-month program. Bone mineral density increased significantly in the immediate treatment group compared with the delayed treatment group during the first 3 months (P<0.001). In addition, HbA(1c) decreased significantly (P=0.001), and self-rated health increased significantly (P=0.012).

CONCLUSIONS

The combination of a laughter and exercise program might have physiological and psychological health benefits for the elderly. Laughter might be an effective strategy to motivate the elderly to participate in physical activity.

Physical activity and health during the menopausal transition

The benefits of regular physical activity are well established, but evidence for a protective effect against the adverse health consequences accompanying the menopausal transition is limited. This article reviews that evidence, concluding that more physical activity is generally associated with fewer somatic and mood symptoms. Physical activity seems to minimize weight gain and changes in body composition and fat distribution experienced at midlife and might attenuate the rapid bone density loss that occurs. Given these benefits, clinicians treating perimenopausal women should encourage their patients to follow guidelines for physical activity (≥150 minutes a week of moderate-intensity activity).

Aerobic exercise and whole-body vibration in offsetting bone loss in older adults

Osteoporosis and its associated fractures are common complications of aging and most strategies to prevent and/or treat bone loss focused on antiresorptive medications. However, aerobic exercise (AEX) and/or whole-body vibration (WBV) might have beneficial effect on bone mass and provide an alternative approach to increase or maintain bone mineral density (BMD) and reduce the risk of fractures. The purpose of this paper was to investigate the potential benefits of AEX and WBV on BMD in older population and discuss the possible mechanisms of action. Several online databases were utilized and based on the available literature the consensus is that both AEX and WBV may increase spine and femoral BMD in older adults. Therefore, AEX and WBV could serve as nonpharmacological and complementary approaches to increasing/maintaining BMD. However, it is uncertain if noted effects could be permanent and further studies are needed to investigate sustainability of either type of the exercise.

A review of exercise interventions to improve bone health in adult cancer survivors

INTRODUCTION

Cancer-treatment induced bone loss and associated fracture risk is a growing concern for cancer survivors. Exercise offers a non-pharmacologic strategy for preserving bone health during and after treatment, but only until recently has it been studied for its efficacy and safety in cancer survivors. The purpose of this review is to provide an early qualitative evaluation of exercise trials in adult cancer survivors with bone health as a primary or secondary endpoint.

METHODS

Databases were searched for exercise trials in adult cancer survivors that reported data on bone health (bone mineral density (BMD) and/or bone remodeling markers) as an outcome measure and were published and indexed prior to January 1st, 2010. Data relevant to evaluation of study design, sample, exercise protocol, bone health assessment, statistical approach and findings were extracted, summarized and interpreted.

RESULTS

Eight trials were identified that met criteria for inclusion in the review. While most studies were conducted in breast cancer survivors, remaining study attributes including rigor, design, exercise program characteristics and length varied considerably across studies. Only three of the eight studies were controlled exercise trials with usual care control groups. Of these, two reported significant group x time interactions where aerobic exercise preserved BMD at the spine or whole body compared to losses in controls and none reported exercise benefits at the hip.

CONCLUSIONS

The recent emergence of exercise studies in cancer survivors with bone outcomes highlights the importance of this area of cancer survivorship. Collectively, the studies are limited in number and are too varied to warrant conclusions regarding the skeletal benefits of exercise during or after cancer treatment, though early results are encouraging and more rigorous study should follow.

[Evidence-based guidelines for physical activity of adult Canadians]

This review of the literature provides an update on the scientific biological and psychosocial bases for Canada's Physical Activity Guide for Health Active Living, with particular reference to the effect of physical activity on the health of adults aged 20-55 years. Existing physical activity guidelines for adults from around the world are summarized briefly and compared to the Canadian guidelines. The descriptive epidemiology of physical activity and inactivity in Canada is presented, and the strength of the relationship between physical activity and specific health outcomes is evaluated, with particular emphasis on minimal and optimal physical activity requirements. Finally, areas requiring further investigation are highlighted. Summarizing the findings, Canadian and most international physical activity guidelines advocate moderate-intensity physical activity on most days of the week. Physical activity appears to reduce the risk for over 25 chronic conditions, in particular coronary heart disease, stroke, hypertension, breast cancer, colon cancer, type 2 diabetes, and osteoporosis. Current literature suggests that if the entire Canadian population followed current physical activity guidelines, approximately one-third of deaths related to coronary heart disease, one quarter of deaths related to stroke and osteoporosis, 20% of deaths related to colon cancer, hypertension, and type 2 diabetes, and 14% of deaths related to breast cancer could be prevented. It also appears that the prevention of weight gain and the maintenance of weight loss require greater physical activity levels than current recommendations.

Exercise and the preservation of bone health

Exercise is generally accepted as having favorable effects on bone health and, subsequently, a reduction in fracture risk. In the absence of large randomized controlled trials of the potential benefits of exercise on fracture risk, support for this belief comes from cross-sectional studies and interventional studies using surrogate endpoints such as bone mineral density and falls. In this review, we discuss the characteristics of exercise programs that provide an osteogenic stimulus. The goals and benefits of exercise on bone across the age spectrum are discussed. Where there is a paucity of human data, animal studies examining the roles of variables such as exercise intensity, frequency, duration, and mode in shaping the response of bone to exercise are discussed. The effects of disuse and the limited response of bone to remobilization are described. The rapid and dramatic decrease in bone mineral density observed in the early period after heart or lung transplantation is discussed, as are the available data on the benefits of exercise on bone in this population. For cardiopulmonary rehabilitation programs to improve bone health, they should include not just weight-supported activities (eg, cycling) but also weight-bearing activities (eg, walking, resistance exercise). Although the optimal exercise routine for bone health is unknown, components of an osteogenic program are discussed.

Evidence-informed physical activity guidelines for Canadian adultsThis article is part of a supplement entitled Advancing physical activity measurement and guidelines in Canada: a scientific review and evidence-based foundation for the future of Canadian physical activity guidelines co-published by Applied Physiology, Nutrition, and Metabolism and the Canadian Journal of Public Health. It may be cited as Appl. Physiol. Nutr. Metab. 32(Suppl. 2E) or as Can. J. Public Health 98(Suppl. 2)

This review of the literature provides an update on the scientific biological and psychosocial bases for Canada’s physical activity guide for healthy active living, with particular reference to the effect of physical activity on the health of adults aged 20–55 years. Existing physical activity guidelines for adults from around the world are summarized briefly and compared with the Canadian guidelines. The descriptive epidemiology of physical activity and inactivity in Canada is presented, and the strength of the relationship between physical activity and specific health outcomes is evaluated, with particular emphasis on minimal and optimal physical activity requirements. Finally, areas requiring further investigation are highlighted. Summarizing the findings, Canadian and most international physical activity guidelines advocate moderate-intensity physical activity on most days of the week. Physical activity appears to reduce the risk for over 25 chronic conditions, in particular coronary heart disease, stroke, hypertension, breast cancer, colon cancer, type 2 diabetes, and osteoporosis. Current literature suggests that if the entire Canadian population followed current physical activity guidelines, approximately one third of deaths related to coronary heart disease, one quarter of deaths related to stroke and osteoporosis, 20% of deaths related to colon cancer, hypertension, and type 2 diabetes, and 14% of deaths related to breast cancer could be prevented. It also appears that the prevention of weight gain and the maintenance of weight loss require greater physical activity levels than current recommendations.

Multiple sclerosis and physical exercise: recommendations for the application of resistance-, endurance- and combined training

This review summarizes the existing knowledge regarding the effects of physical exercise in patients suffering from multiple sclerosis (MS). Furthermore, recommendations are given regarding exercise prescription for MS patients and for future study directions. Previously, MS patients were advised not to participate in physical exercise. During recent years, it has been increasingly acknowledged that exercise benefits MS patients. The requirement for exercise in MS patients is emphasized by their physiological profile, which probably reflects both the effects of the disease per se and the reversible effects of an inactive lifestyle. To date the effects of exercise have only been studied in moderately impaired MS patients with an EDSS score of less than 7. Evidence exists for recommending participation in endurance training at low to moderate intensity, as the existing literature demonstrates that MS patients can both tolerate and benefit from this training modality. Also, resistance training of moderate intensity seems to be well tolerated and to have beneficial effects on MS patients, but the methodological quality of the existing evidence is in general low and the number of studies is limited. Only two studies have evaluated the effects of combined resistance- and endurance training, making solid conclusions regarding this training modality impossible.

Evidence for prescribing exercise as therapy in chronic disease

Considerable knowledge has accumulated in recent decades concerning the significance of physical activity in the treatment of a number of diseases, including diseases that do not primarily manifest as disorders of the locomotive apparatus. In this review we present the evidence for prescribing exercise therapy in the treatment of metabolic syndrome-related disorders (insulin resistance, type 2 diabetes, dyslipidemia, hypertension, obesity), heart and pulmonary diseases (chronic obstructive pulmonary disease, coronary heart disease, chronic heart failure, intermittent claudication), muscle, bone and joint diseases (osteoarthritis, rheumatoid arthritis, osteoporosis, fibromyalgia, chronic fatigue syndrome) and cancer, depression, asthma and type 1 diabetes. For each disease, we review the effect of exercise therapy on disease pathogenesis, on symptoms specific to the diagnosis, on physical fitness or strength and on quality of life. The possible mechanisms of action are briefly examined and the principles for prescribing exercise therapy are discussed, focusing on the type and amount of exercise and possible contraindications.

Health benefits of physical activity: the evidence

The primary purpose of this narrative review was to evaluate the current literature and to provide further insight into the role physical inactivity plays in the development of chronic disease and premature death. We confirm that there is irrefutable evidence of the effectiveness of regular physical activity in the primary and secondary prevention of several chronic diseases (e.g., cardiovascular disease, diabetes, cancer, hypertension, obesity, depression and osteoporosis) and premature death. We also reveal that the current Health Canada physical activity guidelines are sufficient to elicit health benefits, especially in previously sedentary people. There appears to be a linear relation between physical activity and health status, such that a further increase in physical activity and fitness will lead to additional improvements in health status.

Physical training and hormone replacement therapy reduce the decrease in bone mineral density in perimenopausal women: a pilot study

The effects of physical training and hormone replacement therapy (HRT) on bone mineral density in perimenopausal women were studied. Sixty perimenopausal women were randomized to either physical training (n = 20), HRT (n = 20), or control group (n = 20). The study period was 18 months. Bone mineral density (BMD) in the femoral neck and lumbar spine was measured using dual-energy X-ray absorptiometry (DXA). DXA was performed before treatment and after 6 and 18 months. Blood samples for analysis of the bone markers U-deoxypyridinoline and osteocalcin were collected at the same time points. After 18 months, BMD in the spine had not decreased in either the training group or in the HRT group. In the control group, spine BMD had significantly decreased (p = 0.0014). U-Deoxypyridinoline and osteocalcin were increased significantly in the control group (p = 0.0198, p = 0.0295, respectively). No significant changes in bone marker levels were found in the training group or the HRT group. We found that both HRT and physical training can prevent loss of spine BMD in perimenopausal women over a period of 18 months. HRT remains a cornerstone in the treatment of vasomotor symptoms and preservation of BMD. However, HRT can only be used for limited periods of time due to the potential serious adverse effects. This study indicates a beneficial effect of physical activity on spine BMD in the perimenopausal period, and highlights its potential as an alternative to HRT during this period.

Biochemical markers of bone metabolism in healthy elderly men. The relationship to physical activity

The purpose of the present study was to examine the serum levels of bone turnover markers and interleukin 1beta in healthy elderly men with different levels of habitual physical activity. The study was conducted on 40 healthy men aged between 65 and 85 years (mean 74.0 +/- 7.55 years). The study population was divided into two groups with respect to the level of physical activity: 22 less active subjects (energy expenditure related to physical activity below 1600 kcal per week) and 18 more active subjects (above 1600 kcal per week). To estimate the physical activity of the study population, weekly energy expenditure was measured in each subject with use of Caltrac accelerometer. In the blood serum levels of bone formation marker--osteocalcin and resorption marker--the C-terminal telopeptide of collagen I (ICTP), and interleukin-1beta were determined. Concentrations of osteocalcin and ICTP in less active subjects were significantly higher (by 3.62 ng/ml and by 1.21 mug/l respectively, p < 0.05), reflecting the higher bone turnover in comparison to values determined in more active subjects. Positive correlations between ICTP and osteocalcin levels (r = 0.5814 and r = 0.6526; p < 0.05), and between ICTP and IL-1beta (r = 0.5823 and r = 0.6040; p < 0.05) in less and more active men were found. On the ground of the presented study it can be concluded that the decreased bone turnover occurred in men with higher level of habitual physical activity. This study showed the relationship between serum level of IL-1beta and bone resorption but the habitual physical activity has no effect on this cytokine activity.

The effect of physical training on bone mineral density in women with endometriosis treated with GnRH analogs: a pilot study

BACKGROUND

The effect of physical training on bone mineral density (BMD) in women with endometriosis treated with gonadotropin-releasing hormone (GnRH) analogs was studied.

METHODS

Nineteen Caucasian premenopausal women aged 23-38 years were included in the study. The subjects were all treated with 21.6 mg goserelin during 6 months. The patients were randomized to physical training n=8 or to a control group n=11. The total period of training was 12 months, whereas GnRH treatment was terminated after 6 months. BMD was measured in the femoral neck area and the lumbar spine using dual X-ray absorptiometry (DEXA). This was performed just before treatment, after 6 months and after 12 months. Six women fulfilled the training during 12 months of observation. In the control group 10 women were followed up for 12 months.

RESULTS

After 6 months the women in the physical training group were 2.1% below baseline. Six months later these women had gained BMD in the femoral neck and were 0.6% below baseline. Those in the control group lost 2.8% after 6 months and were 3.6% below baseline after 12 months. The difference in loss of BMD after 12 months between the groups was significant 0.029. In the spine there was no significant difference between the two groups.

CONCLUSIONS

Physical training in women with endometriosis was found to rebuild bone after treatment with GnRH analogs when compared to a control group. This effect could be demonstrated 6 months after cessation of GnRH treatment.

Exercise and aging

There is increasing evidence that the black box we have referred to as"biologic aging" is composed of genetic factors and many types of environmental exposures. Some of the most potentially modifiable elements of this syndrome are those attributable to disuse or insufficient exposure to certain kinds or intensities of physical stressors during the course of the life span. Beneficial adaptations to exercise once thought restricted to genetically endowed master athletes now are seen to occur just as predictably in frail elders with chronic disease, opening the door to vastly improved physical function and associated health benefits. Knowledge of the benefits of physical activity, however well substantiated, may be necessary, but it is not sufficient to change either physician-prescribing habits or the likelihood of adoption and long-term adherence to exercise on the part of patients. Ultimately, the penetration of an exercise prescription to optimize aging into the most inactive cohorts in the community,who have the most to gain from increases in levels of physical activity and fitness, will depend on a combination of clear evidence-based guidelines coupled with health professional training and behavioral programs tailored to age-specific barriers and motivational factors.

Bone mineral density in postmenopausal women: does exercise training make a difference?

Although postmenopausal women are encouraged to exercise to preserve bone mineral density (BMD), few studies have looked at what type of exercise is most effective.

Are Cardiovascular Disease and Osteoporosis Directly Linked?

For years, osteoporosis and cardiovascular disease were thought to be two independent consequences of aging; however, mounting evidence supports an association between these diseases. Recently, a widespread class of cholesterol-lowering drugs known as statins have demonstrated (in rodents and cell cultures) the ability to induce bone formation. This finding is significant since current therapies are limited to the prevention or slowing down of bone loss rather than (enhancing/improving) bone formation. In humans, the ability of statins to generate new bone has not been consistent; however, several investigations have demonstrated a dramatic decrease in fracture risk. Although it has been proposed that statins induce new bone via increased bone morphogenetic protein-2, other conditions affected by statins such as dyslipidaemia, vascular calcification, endothelial dysfunction and impaired nitric oxide expression, may also contribute to the cardiovascular and bone health paradigm. Furthermore, the role of physical activity and its influence on cardiovascular and bone health, especially in postmenopausal women, may contribute to the discrepancy of findings in human data. In summary, it remains to be determined if statins contribute to bone health via improvements in vascular health or by pleiotropic properties unique to their pharmacology. This review provides information on our current understanding of the bone and cardiovascular association, as well as on novel areas of research to further our current understanding of these conditions.

Socioepidemiologic and Health-Related Correlates of Walking for Exercise among the Elderly: Results from the Longitudinal Study of Aging

Walking for exercise might counteract the effects of a sedentary lifestyle. We examined the demographic and health-related predictors of walking 1 mile per week or more among the elderly. Data were from the 1984 Longitudinal Study of Aging. Participants were 7,527 adults age 70 years or older. Demographic factors related to walking were younger age, college-level education, being unmarried, and higher income. Health-related variables associated with walking included positive self-perception of health, internal health locus of control, and absence of activity limitations. The prevalence of regular walking for exercise was low in the study population (38% and 26% for men and women, respectively). Interventions that increase the internal health locus of control might be effective in increasing walking among the elderly.

Exercise and lumbar spine bone mineral density in postmenopausal women: a meta-analysis of individual patient data

BACKGROUND

Low bone mineral density (BMD) at the lumbar spine is a major public health problem among postmenopausal women. We conducted a meta-analysis of individual patient data (IPD) to examine the effects of exercise on lumbar spine BMD in postmenopausal women.

METHODS

IPD were requested from a previously developed database of summary means from randomized and nonrandomized trials dealing with the effects of exercise on BMD. Two-way analysis of variance tests with pairwise comparisons (p < or =.05) and 95% confidence intervals (CIs) were used to determine the statistical significance for changes in lumbar spine BMD.

RESULTS

Across 13 trials that included 699 subjects (355 exercise, 344 control), a statistically significant interaction was found between test and group (F = 15.232, p =.000). Pairwise comparisons (Bonferroni t tests) revealed a statistically significant increase in final minus initial BMD for the exercise group ( +/- SD = 0.005 +/- 0.043 g/cm(2), t = 2.46, p =.014, 95% CI = 0.001-0.009) and a statistically significant decrease in final minus initial BMD for the control group ( +/- SD = -0.007 +/- 0.045 g/cm(2), t = -3.051, p =.002, 95% CI = -0.012--0.002). Changes were equivalent to an approximate 2% benefit in lumbar spine BMD (exercise, +1%, control, -1%).

CONCLUSIONS

The results of this IPD meta-analysis suggest that exercise helps to improve and maintain lumbar spine BMD in postmenopausal women.

Bone-loading response varies with strain magnitude and cycle number

Mechanical loading stimulates bone formation and regulates bone size, shape, and strength. It is recognized that strain magnitude, strain rate, and frequency are variables that explain bone stimulation. Early loading studies have shown that a low number (36) of cycles/day (cyc) induced maximal bone formation when strains were high (2,000 microepsilon) (Rubin CT and Lanyon LE. J Bone Joint Surg Am 66: 397-402, 1984). This study examines whether cycle number directly affects the bone response to loading and whether cycle number for activation of formation varies with load magnitude at low frequency. The adult rat tibiae were loaded in four-point bending at 25 (-800 microepsilon) or 30 N (-1,000 microepsilon) for 0, 40, 120, or 400 cyc at 2 Hz for 3 wk. Differences in periosteal and endocortical formation were examined by histomorphometry. Loading did not stimulate bone formation at 40 cyc. Compared with control tibiae, tibiae loaded at -800 microepsilon showed 2.8-fold greater periosteal bone formation rate at 400 cyc but no differences in endocortical formation. Tibiae loaded at -1,000 microepsilon and 120 or 400 cyc had 8- to 10-fold greater periosteal formation rate, 2- to 3-fold greater formation surface, and 1-fold greater endocortical formation surface than control. As applied load or strain magnitude decreased, the number of cyc required for activation of formation increased. We conclude that, at constant frequency, the number of cyc required to activate formation is dependent on strain and that, as number of cyc increases, the bone response increases.

Dose-response of physical activity and low back pain, osteoarthritis, and osteoporosis

PURPOSE

The purpose of this study was to examine the evidence for causal relationships between physical activity (PA) and low back pain (LBP), osteoarthritis (OA), and osteoporosis (OP), and for dose-response relations involved.

METHODS

Computer database searches and personal retrieval systems were used to locate relevant literature.

RESULTS

PA can be effective in preventing LBP (Category A) but prolonged, heavy loading can lead to LBP (Category C). Specific exercises have not been found effective in treatment of acute LBP (Category A), but PA can be effective in chronic LBP (Category B), especially for diminishing the effects of deconditioning. No evidence indicates that PA directly prevents OA. Large amounts of intensive PA involving high impacts or torsional loadings or causing injuries increases risk of OA (Category C). Light or moderate PA does not increase the risk of OA (Category C). PA can be effective in the treatment and rehabilitation of OA (Category B). High-intensity loading is osteogenic and possibly useful in prevention of OP (Category A) at the loaded site, but low to moderate loading is not osteogenic (Category D). Static efforts and slow movements are ineffective or less effective than fast application of force (Category B). The types of PA to attain the effects mentioned above are known except in the case of prevention of LBP, but dose-response relationships are poorly known; at best, semiquantitatively on the basis of just a few studies.

CONCLUSION

Given the shown primary and/or secondary preventative effectiveness of PA regarding LBP, OA, and OP, research to elucidate the inadequately known dose-response relations should be given high priority.

Resistance training and bone mineral density in women: a meta-analysis of controlled trials

The purpose of this study was to use meta-analysis to examine the effects of resistance training on bone mineral density at the femur, lumbar spine, and radius in pre- and postmenopausal women. Resistance training had a positive effect on bone mineral density at the lumbar spine of all women and at the femur and radius sites for postmenopausal women. It was concluded that resistance training has a positive effect on bone mineral density in women.

Leisure time physical activity in Australian women: relationship with well being and symptoms

This paper explores the association between moderate levels of physical activity (PA) and health benefits in well being and symptoms such as tiredness, back pain, and constipation. Participants in the Australian Longitudinal Study on Women's Health, 14,502 young women (ages 18-23 years), 13,609 middle-age women (45-50 years), and 11,421 older women (ages 70-75 years), answered questions about vigorous and less vigorous exercise (used to determine a physical activity score), well being (SF-36), symptoms, and medical conditions. There were significant associations between the PA score and SF-36 in each cohort. Odds ratios (OR) for a range of symptoms and conditions were lower for women who reported low to moderate activity than for sedentary women, for example, for young women or for constipation = 0.76 (CI, 0.65-0.89), for middle-age women or for tiredness = 0.70 (0.63-0.78). There was no threshold of PA at which health benefits increased significantly. Although cross-sectional, the findings suggest that low-to-moderate levels of exercise are associated with a range of health benefits for women of all ages. These preliminary findings will be followed up during the longitudinal study.

Physical activity, falls, and fractures among older adults: a review of the epidemiologic evidence

OBJECTIVES

Assess the relationship between physical activity and risk for falls and osteoporotic fractures among older adults.

DESIGN

Review and synthesis of published literature.

MEASUREMENTS

We searched the literature using MEDLINE, Current Contents, and the bibliographies of articles identified. We included randomized controlled trials (RCT) of the effects of physical activity on the incidence of falls and case-control and prospective cohort studies of the association of physical activity with osteoporotic fracture risk. We also summarized mechanisms whereby physical activity may influence risk for falls and fractures.

RESULTS

Observational epidemiologic studies and randomized clinical trials evaluating the effectiveness of physical activity programs to prevent falls have been inconclusive. However, many studies have lacked adequate statistical power, and recent trials suggest that exercise, particularly involving balance and lower extremity strength training, may reduce risk of falling. There is consistent evidence from prospective and case-control studies that physical activity is associated with a 20-40% reduced risk of hip fracture relative to sedentary individuals. The few studies that have examined the association between physical activity and risk of other common osteoporotic fractures, such as vertebral and wrist fractures, have not found physical activity to be protective.

CONCLUSIONS

Epidemiologic studies suggest that higher levels of leisure time physical activity prevent hip fractures and RCTs suggest certain exercise programs may reduce risk of falls. Future research needs to evaluate the types and quantity of physical activity needed for optimal protection from falls and identify which populations will benefit most from exercise.

Exercise and bone mineral density in men: a meta-analysis

The purpose of this study was to use the meta-analytic approach to examine the effects of exercise on bone mineral density (BMD) in men. A total of 26 effect sizes (ES) representing 225 subjects from 8 studies met the criteria for inclusion. When BMD sites assessed were specific to the sites loaded during exercise, increases of approximately 2.6% (2.1% in the exercisers and -0.5% in the controls) were found. These results were statistically significant (ES = 0.213, 95% bootstrap confidence interval = 0.007-0.452). Statistically significant ES changes were found for older (>31 yr) but not younger (<31 yr) adults, with differences between groups statistically significant (P = 0.04). Statistically significant changes were also observed at the femur, lumbar, and os calcis sites. The results of this study suggest that site-specific exercise may help improve and maintain BMD at the femur, lumbar, and os calcis sites in older men. However, the biological importance of the small changes observed for most outcomes, quality of studies, and limited data pool prevent us from forming any firm conclusion regarding the use of exercise for maintaining and/or improving BMD in men. Clearly, a need exists for additional studies.

Position of the American Dietetic Association and Dietitians of Canada: women's health and nutrition

Within the past 10 years women's health has evolved to a much broader paradigm, beyond reproductive issues. From a physiological perspective, women's health now refers to the prevention, diagnosis, and management of conditions or diseases that may be unique to women, be more prevalent in women, or manifest differently in women than men. Women's health encompasses emotional, social, cultural, spiritual, and physical well-being. It is determined by the social, political, and economic context of women's lives. Nutrition is involved in the etiology or treatment of half of the 10 leading causes of death in women. The incidence of osteoporosis and extremes in body weight are approaching epidemic proportions in women. This position reviews the following health problems: cardiovascular disease, cancer, osteoporosis, weight, and diabetes mellitus. Dietetics professionals are in the perfect position to understand the issues surrounding women's health in order to deliver a message to women that will allow them to make wise decisions regarding their health. Nutrition is a critical component of risk reduction and treatment, and must be included in clinical and preventive services for women. Dietetics professionals must work to increase their knowledge about women's health issues, to promote health and education programs, to influence policy makers, to deliver the highest-quality medical nutrition therapy, and to be proactive in documenting the effectiveness of outcomes-based research.